The field of the present invention relates to optical scanning systems and particularly to an aiming system and method for use with an optical scanning system. The aiming system is especially suitable for use with a laser scanner for reading optically readable codes such as those found on consumer and industrial products, most frequently bar code and other symbols.
Bar code scanners, as any optical system, require outgoing scan beam to be properly drawn over the intended target such as the bar code. Handheld laser scanners normally form a single scan line which must be aimed to traverse the entire bar code. Over longer distances, which for long range scanner may be several feet, scan lines become diffuse such that they are not readily visible on a target, making it difficult for the operator to properly aim the scanner at the target or effectively manipulate the target to be read. In response to this problem, laser scanners such as described in U.S. Pat. Nos. 4,603,262 and 5,296,689 have been developed employing a pointer beam or aiming light which is visible over a greater distance to aid the user in aiming the handheld scanner.
In fixed scanners, the scan patterns tend to be multidirectional, generating a complex scan pattern forming a scan volume. Items to be scanned are passed through the scan volume and the bar code on the item is read. Such a scanner is the PSC Inc. Magellan T scanner (formerly sold under the Spectra-Physics Scanning Systems, Inc. label) which is described in U.S. Pat. No. 5,475,207. Aiming beams are not required for fixed scanners primarily because the scan volume through which the item is being passed is typically more intuitive, the checkout clerk learning to orient the item with the bar code facing a window.
Nonetheless, the present inventors have recognized the potential to facilitate scanning in the fixed scanner environment.